This application involves an improvement over certain features of the above-mentioned patent. Specifically this invention provides an improved sleeve valve assembly to replace that disclosed in FIGS. 6 and 7 of the incorporated Read patent.
The cited portions of the Read patent disclose a valve sleeve having a mandrel with external gudgeon pins and a pair of ports spaced 180.degree. apart around the valve. An elastomeric seal sleeve is located on the inside surface of the valve sleeve.
Although the valve assembly of the Read patent is a significant improvement over the existing art and performs well, it was desirable to obtain a valve assembly having seals with great sealing ability but with reduced resistance to rotation.
This invention provides such a valve assembly utilizing replaceable metal seal inserts having a peripheral seal area on one or both sides and capable of obtaining pressure balancing across the seal area.